The Soviet Union still falls apart and whatever emerges leans strongman eventually, but minus the personalities
I'm a bit of a Yeltsin aficionado. It's not that he wasn't vain, and at times ridiculous, or hopelessly corrupt, but he was also genuine or as genuine as the head of government of massive power in the 20th century can become, and he was crucial to the dismemberment of the Soviet beast, but if he wasn't there, someone else would have come along to spear the dragon.
Someone in a position of power in Moscow or Leningrad would have harnessed the bitterness and resentment and used it against the Party and then realized the Party and its apparatus could not or would not do anything to truly destroy him. It was only a matter of time. The problems in society were there. The lack of stability was there. The military was not willing to be made scapegoats in event of having to be used to put down a rebellion. The secret police was not willing to dirty their hands. The entire thing was wheezing and on rubber legs. Yeltsin just happened to be the guy who landed the shot.